Samsung CLP-680 Series Service Manual page 114

4. Alignment and Troubleshooting
3) Contamination on back of page
• Description : The back of the page is contaminated.
Cause and Check Point
Dirty registration roller, pressure roller, feed roller, etc.
Any dirty rollers through the path of the paper.
Check if the transfer roller is damaged or contaminated.
Check if paper transfer belt is damaged or contaminated.
4) Dark or Black image
• Description : The black page is printed out.
Cause and Check Point
No charging voltage in the HVPS.
Poor contact between toner cartridge and set contacts.
HVPS is defective.
4-50
Solution
Identify the roller which may cause the problem by
comparing the period of the contamination on images with
the size of rollers. Clean any dirt from the roller or replace
the dirty roller.
Replace the transfer roller and test again.
Replace the ITB unit and test again.
Solution
Check the connecting state between the Main PBA and
HVPS. Reconnect the harness.
Clean the contacts as necessary. Replace any deformed
or damaged contacts.
Replace the HVPS.
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